The prior art generally discloses various systems for remotely monitoring various information or parameters within vending machines, such as inventory changes, alarm conditions, cash receipts, etc., wherein the information may be transmitted to a central site for subsequent analysis.
For instance, Sedam et al. U.S. Pat. No. 4,412,292 (hereinafter "Sedam") discloses such a system for remotely monitoring a vending machine and for automatically transmitting pertinent information to a central computer. While Sedam, FIG. 2, teaches using a telephone line to connect the remote monitor to the computer, Sedam also suggests that a radio means may alternately be used. See Sedam, col. 4, lines 55-62.
Cedrone et al. U.S. Pat. No. 4,766,548 (hereinafter "Cedrone") further discloses such an arrangement, suggesting that a radio link may be used to link the remote monitor device to the central computer. See Cedrone, col. 3, lines 17-21.
In summary, reporting systems using radio frequency communications to link a remote monitoring device to a central computer are suggested in the prior art.
However, there are problems with such arrangements. One problem is how to keep the monitoring devices within RF range of the base station. Since the monitoring devices are typically physically secured to a vending machine, the radio communication link may be degraded, or even destroyed, if the associated vending machine is moved to a different location, or if other factors related to RF propagation change. Thus, with a single base site, the area of communication coverage may be limited.
One suggested approach to this problem has been to provide increased coverage by providing multiple base station sites. However, this is expensive, since additional base station hardware is needed. Also, problems arise when the coverage area from different base sites overlap. In addition, each base station must typically be equipped with its own dedicated telephone line in order to couple to the central computer, therefore increasing monthly network charges from the serving telephone company to provide the extra facility.
As a result, there is a need for an improved reporting system.